Luminal loss and restenosis after coronary angioplasty. The role of lipoproteins and lipids

AIMS

Lipoproteins and lipids, especially lipoprotein(a), have been studied as risk factors for restenosis after coronary angioplasty with conflicting results. We investigated the association between serum levels of lipoprotein(a) apolipoprotein A-1, apolipoprotein B-100, total-cholesterol, high density lipoprotein-cholesterol, triglycerides, and coronary luminal loss and restenosis after angioplasty.

METHODS

The lipoproteins and lipids were measured in 305 consecutive patients who underwent successful angioplasty and reangiography 20+/-3 weeks after angioplasty. Single-vessel dilatation was performed in 251 patients. Luminal loss was defined as minimal luminal diameter post-angioplasty minus minimal luminal diameter at follow-up, divided by the interpolated reference diameter of the vessel. Restenosis was defined according to three dichotomous categorical criteria: (1) >50% diameter stenosis at follow-up (2) loss of >50% of the gain achieved by angioplasty, (3) the need for target vessel revascularization.

RESULTS

There was no significant association between the serum levels of lipoproteins and lipids and luminal loss. Univariate analysis did not show any significant difference in the serum levels of any of the lipoproteins and lipids between the restenosis and no-restenosis groups. Multivariate analysis revealed that only the angiographic variables (luminal gain and post-angioplasty minimal luminal diameter) were associated with luminal loss and restenosis after angioplasty.

CONCLUSION

Lipoproteins and lipids were neither associated with luminal loss nor independent risk factors for restenosis after angioplasty.

[Utilization of anti-infective agents in pediatric departments in health region 2]

Children are often treated with antiinfective drugs, both in and out of hospital, but few studies of antiinfective drug use in paediatric departments have been published. We have analysed the dispensing of antiinfective drugs from hospital pharmacies to all eight paediatric departments in south-eastern Norway (Health region 2) during the years 1990-95. The total consumption of antiinfective drugs, measured by the number of defined daily doses (DDD), did not increase during the study period, though the total costs for such drugs increased by 48% for all eight departments. In 1995 the antiinfective drug use varied between 15 and 30 defined daily doses per 100 bed days. The total use of cephalosporins increased significantly. For vancomycin, antifungal drugs and antiviral agents, both consumption and cost increased in several departments. Knowledge of the total use of antiinfective drugs may be important when evaluating treatment regimens, especially with regard to microbial resistance.

The T cell receptor repertoire of CD8+CD28- T lymphocytes is dominated by expanded clones that persist over time

The costimulatory molecule CD28 is expressed on almost all CD4+ T cells, but on only a portion of CD8+ T cells in healthy human adults. alpha beta T cells may thus be divided into three phenotypically and functionally different subsets: CD4+, CD8+CD28+ and CD8+CD28-. Using peripheral blood lymphocytes from six healthy adults, we have studied the T cell receptor (TCR) repertoire within these subsets by analysis of the distribution of lengths of the complementarity determining region 3 (CDR3) of the beta variable (BV) transcripts and flow cytometric analysis of TCR V beta usage. Expanded CDR3 lengths were identified in 86% of BV families within CD8+CD28- T cells, but in only 4% within CD4+ T cells, and 35% within CD8+CD28+ T cells (P < 0.01). When sequenced, the majority of expanded peaks were found to be dominated by single clones. Identical expanded clones were found within both CD8+CD28+ and CD8+CD28- subsets, consistent with the belief that CD8+CD28- T cells descend directly from CD8+CD28+ T cells. Greatly expanded CD28- clones were found within both CD8+ and CD4+ subsets and persisted at the same magnitude for up to 4.5 years of observation. The finding of a small proportion of cells expressing Ki-67 showed that some of these clonally expanded cells were in the active stages of the cell cycle, but few of the cells expressed activation markers CD69, CD25, CD71 or CD122. One likely explanation for the persistence of expanded peripheral lymphocyte populations in healthy individuals is the presence of persistent antigen.

Thrombopoietin combined with early-acting growth factors effectively expands human hematopoietic progenitor cells in vitro

Thrombopoietin (TPO) is established as a powerful stimulant of megakaryocyte differentiation and platelet production both in vivo and in vitro. In preparation for future transplantation of ex vivo expanded CD34+ hematopoietic progenitor cells (HPCs), we have examined the in vitro effect of TPO on cultures of HPC when combined with other early-acting hematopoietic growth factors (GFs) in an attempt to decrease post-transplant thrombocytopenia and accelerate engraftment. By adding TPO to all possible combinations of GM-CSF, IL-3, and c-kit ligand (CKL) in a suspension culture system, we found a significant increase in both relative and absolute numbers of cells in cultures containing TPO of the megakaryocytic lineage and CD34+ cells after 14 days of culture. The most efficient GF combinations for expansion of cell populations of the megakaryocytic lineage and HPCs were TPO, GM-CSF, and CKL, which increased the number of cells of the megakaryocytic lineage 78 fold and the number of CD34+ cells 1.8 fold. The number of CD34+ cells decreased in the cultures containing GM-CSF and CKL with no TPO present, and the number of cells of the megakaryocytic lineage was increased merely 27 fold. Based on our findings, we suggest adding cells from HPCs expanded in cultures containing TPO, GM-CSF, and CKL to unexpanded stem cells for stem cell transplantation.

Molecular analysis of the complementarity determining region 3 of the human T cell receptor beta chain. Establishment of a reference panel of CDR3 lengths from phytohaemagglutinin activated lymphocytes

The T cell receptor (TCR) repertoire of a lymphocyte population may be characterized by the distribution of lengths of the hypervariable fragment known as the complementarity determining region 3 (CDR3). Immunological activity leading to clonal predominance will result in an over-representation of given CDR3 lengths and a distortion of the CDR3 length distribution. CDR3 length distribution may be studied by the in vitro amplification of TCRB cDNA followed by gel electrophoresis of the resulting product. We have established a simple, robust method for the evaluation of CDR3 length distribution in human lymphocyte samples. The CDR3 length distribution in phytohaemagglutinin (PHA) activated lymphocytes from a large number of healthy donors was established as a reference panel for each of 22 human TCR beta variable (BV) families. We propose that an abnormal CDR3 length distribution be defined as one in which one or more CDR3 lengths exceed the upper confidence limit (5% significance, one-sided test) given by this PHA reference population. Using this criterion in titration experiments, we were able to identify a clone when it constituted 2% of the cells analyzed. Over-dilution of cellular material or cDNA may produce falsely abnormal CDR3 length distributions. A nested technique using two separate amplification steps was found to yield results comparable in quality to the single amplification technique. When few cells are available, the nested method gives more material for CDR3 length analyses. However, it does not reduce the likelihood of a falsely abnormal distribution being recorded when the cellular material is too scarce.

Is a prolonged bleeding time associated with an increased risk of hemorrhage after liver biopsy?

Bleeding time determination is not advised as a general preoperative hemostasis screening test, but it might be useful in some patient groups. Patients referred for liver biopsy frequently have coagulation disturbances and are at risk of hemorrhage. In this prospective study 219 liver biopsies were carried out regardless of a prolonged bleeding time, but with minimum requirements for hemoglobin concentration, platelet count, and tests of the internal and external coagulation pathways. The bleeding time was prolonged in the case of 48 (22%) of the biopsies. Significant bleeding as defined by a hemoglobin decrease of > or =2.0 g/dl occurred in nine patients. Three of these patients were bone marrow transplanted. Patients with a prolonged bleeding time carried a five times higher risk of bleeding (odds ratio = 5.0; confidence interval = 1.1-21.8; p = 0.019). We conclude that the bleeding time may give additional information on the risk of bleeding in some patient groups undergoing liver biopsy.

Prognostic significance of CT contrast enhancement within histological subgroups of intracranial glioma

We report the prognostic significance of tumor CT contrast enhancement within histological subgroups in 831 consecutive adult glioma patients of high-grade (n = 516) and low-grade (n = 315) histology. In the present report, a negative prognostic factor is associated with shortened survival.

METHODS

Survival analysis including Kaplan-Meier plots, log-rank tests, Cox analysis, and Aalen's linear model as implemented in SPSS and S-PLUS.

RESULTS

Sensitivity and specificity of contrast enhancement as a test for high-grade glioma was 0.87 and 0.79, respectively. Enhancement was a strong negative prognostic factor comparable to high-grade histology in the total patient population. Enhancement was also a negative prognostic factor within the subgroups adult high-grade (Grade 3-4), anaplastic (Grade 3), and low-grade (Grade 1-2) gliomas (p < 0.001). The prognostic implications of initial enhancement declined in high-grade patients surviving beyond 36 months. Tumor contrast enhancement or calcifications (in parentheses) were present in 96% (3.6%) of glioblastomas, in 87% (7.4%) of high-grade gliomas, in 56.5% of anaplastic gliomas, and in 21% (16.2%) of low-grade gliomas. Calcification was a positive prognostic factor within the high-grade group of patients (p < 0.0001).

CONCLUSION

Enhancement was a major prognostic factor comparable to high-grade histology in this glioma patient population. Enhancement was a negative prognostic factor within each of the adult subgroups high-grade, anaplastic (grade 3), and low-grade gliomas. Enhancement was strongly associated with but not pathognomonic for high-grade histology.

Increased number of substitutions in the D-loop of mitochondrial DNA in the sudden infant death syndrome

The purpose of the present study was to investigate substitutions in the D-loop of mitochondrial DNA (mtDNA) in sudden infant death syndrome (SIDS) and controls, since several observations indicate the involvement of mtDNA mutations in SIDS. These include elevated levels of vitreous humour hypoxanthine in SIDS victims, familial clustering without mendelian traits, and observations of increased sleepiness and a lower activity score in infants who later succumbed to SIDS. Eighty-two cases of SIDS and 133 controls were investigated and the D-loop sequences were recorded in the base-pair range 16055-16500 in the mtDNA sequence. The sequencing was carried out using the Applied Biosystems Sequenase dye terminator method and a ABD373A sequencer. The recorded D-loop sequences were compared with the Cambridge sequence and differences were recorded as substitutions. The SIDS cases had a tendency towards a higher substitution rate in the D-loop than the controls (p = 0.088). This observation makes it interesting to search for deleterious mutations in other locations in the mtDNA.

The CD34 molecule and hematopoietic progenitor cell studies--a challenge in clinical medicine

The CD34 molecule, which is expressed at various levels on virtually all human hematopoietic progenitor cells (HPC), is a heavy glycosylated molecule with many different epitopes. A large series of CD34-specific monoclonal antibodies specific for different epitopes has been generated. Some of these antibodies do not react with particular HPC subpopulations. Thus, the antibodies used for HPC enumeration and isolation have to be carefully chosen with respect to what is aimed at.

CD34 molecule epitope distribution on cells of haematopoietic origin

The CD34 molecule belongs to the mucin membrane molecule family and is expressed on virtually all normal haematopoietic progenitor cells (HPC). Due to its heavy glycosylation, several different epitopes exist on the molecule. Based on the sensitivity of the glycosylated molecule to degradation with a glycoprotease from Pasteurella haemolytica and neuraminidase, three classes of epitopes have been identified. The class I and II epitopes are probably related to the glycosylated part of the molecule while class III epitopes are core protein related. It has been known for some time that CD34 class I epitopes are absent on CD34 molecules expressed on high endothelial venules. Here we review recent observations that expression of both class I and II epitopes, but not class III epitopes, is impaired on mature myeloid CD34-pos. HPC while no diverse class epitope expression was observed on immature HPC. In addition, cells from patients with CD34-pos. acute myeloid leukaemia of FAB classification M4-M5, i.e., leukaemic blast cells of relatively mature morphologic phenotype, also express less class I and II epitopes than class III epitopes. It therefore seems that HPC maturation and class I and II epitope deprivation are concomitant events and that CD34 class I and II epitopes are lost prior to downregulation of the CD34 molecule per se. The biological significance of this observation is discussed as well as the need to carefully select CD34-specific monoclonal antibodies for research and clinical purposes.

Demonstration of identical expanded clones within both CD8+CD28+ and CD8+CD28- T cell subsets in HIV type 1-infected individuals

In HIV-1-infected individuals, the CD8+CD28- T cell subset is considerably expanded and is frequently the largest subset of T cells found in peripheral blood. It has been assumed, but not proven, that CD8+CD28- T cells derive from CD8+CD28+ T cells in vivo. To further study the ontogeny of CD8+CD28- T cells, we have performed analyses of the complementarity determining region 3 (CDR3) of the TCRB of CD8+CD28+ and CD8+CD28- T cells from the peripheral blood of HIV-1-infected individuals. When cells from the same individual were compared, expanded peaks in CDR3 length analysis within a given BV family were frequently observed at the same location in both CD8+ subsets (p < 0.001). Sequencing of cDNA corresponding to dominant peaks revealed the presence of identical expanded CD8+ T cell clones within both the CD28+ and CD28- subsets on eight of nine attempts. Our results show that CD8+CD28+ and CD8+CD28- T cells are phenotypic variants of the same lineage, most likely evolving from CD8+CD28+ to end-stage CD8+CD28- T cells.

Effects of anal invasive treatment and incontinence on mental health and psychosocial functioning of adolescents with Hirschsprung's disease and low anorectal anomalies

BACKGROUND/PURPOSE

Recent studies of adolescents with Hirschsprung's disease (HD) and low anorectal anomalies (LARA) showed persistent impairment of fecal control in both groups, but very different mental and psychosocial outcome.

METHODS

To explore possible reasons for these differences, 19 adolescents with HD (aged 10 to 20 years; median, 16) operated on by the Duhamel technique were compared with 17 adolescents with LARA (aged 12 to 20 years; median, 15). The 36 adolescents were assessed for treatment procedures, bowel function, and mental and psychosocial outcome by data collected from medical records, physical examination, semistructured interview, and standardized questionnaires. The parents of 30 adolescents were also interviewed and completed questionnaires.

RESULTS

Duration of anal invasive treatment procedure and current bowel function were associated with mental and psychosocial outcome. The treatment variable, duration of anal dilation, was the most significant predictor of the adolescents's mental health (R2 = .41, P < .01), whereas chronic family difficulties and parental warmth together with the current bowel function variables, fecal and flatus continence function, best explained the variance in psychosocial outcome (R2 = .77, P < .0001). Thus, the differences in treatment procedures and continence function between the HD and LARA groups may partially explain differences in mental and psychosocial outcome.

CONCLUSIONS

These findings suggest that anal dilatation and continence dysfunction may have negative impact on mental health and psychosocial functioning. Indications for and ways of performing the procedure of dilation, and the treatment of persistent incontinence problems, are questioned.

Efflux of CD34+ cells from bone marrow to peripheral blood is selective in steady-state hematopoiesis and during G-CSF administration

Comparative studies of the CD34+ cell population in peripheral blood (PB) and bone marrow (BM) may contribute to understanding the mechanisms involved in mobilization of hematopoietic progenitor cells (HPCs) from BM to PB. PB-CD34+ and BM-CD34+ cells in steady-state hematopoiesis and during granulocyte colony-stimulating factor (G-CSF) administration were studied for the expression of activation-associated, lineage-associated and adhesion-associated molecules and for their cloning capacity [granulocyte-macrophage colony-forming cells (CFU-GM) and burst-forming unit-erythrocytes (BFU-E)]. G-CSF increased significantly the number of CD34+ cells in PB as well as in BM and resulted in a reduction of CD34+ cells coexpressing the adhesion-related molecule CD49d. Further, G-CSF reduced the relative number of lymphoid progenitors (CD34+ cells coexpressing CD10, CD19, CD20, CD2, or CD7) in both compartments. However, G-CSF had no major impact on the observed differences between PB-CD34+ and BM-CD34+ cells seen during steady-state hematopoiesis despite a relative decrease in PB and increase in BM of certain immature progenitors (CD34+DR- cells). Circulating CD34+ cells, even in steady-state, were enriched for colony-forming cells, and individual colonies appeared larger compared with their BM counterparts. PB-CD34+ cells contained relatively more myeloid progenitors (CD34+CD13+ cells) and fewer B lymphoid progenitors (CD10, CD19, and CD20 cells) than BM-CD34+ cells. CD34+DR-cells were present in a higher proportion of the CD34+ cells in PB than in BM. There were lower numbers of CD34+ cells expressing CD49d and c-kit in PB than in BM. To summarize, the differences between PB-CD34+ and BM-CD34+ cells observed during steady-state hematopoiesis were largely conserved during G-CSF administration. G-CSF, therefore, mainly has an effect on the quantity not the composition of the circulating CD34+ cell pool. Our data also suggest that the egress of HPCs from BM during steady-state hematopoiesis, as well as during G-CSF administration, is a selective process; that is, certain subsets are more prone to enter into circulation than others, and this release may be mediated via common pathway possibly involving downregulation of c-kit and VLA-4 (CD49d).

Hodgkin's disease in a national and hospital population: trends over 20 years

The aim of the study was to investigate the incidence rate and time trends in a national registry population of Hodgkin's disease (HD) and the effects of selection in a hospital population. A national registry population of all HD patients from Norway and a hospital population of HD patients treated at the Norwegian Radium Hospital (NRH) were studied retrospectively from 1971 to 1993. The incidence of non-Hodgkin's lymphomas (NHL) in Norway increased steadily from 1961 in contrast to a stable incidence pattern for HD before 1980 and a decreasing incidence since 1980. Due to improved diagnostic tools after 1980, an increasing proportion of patients previously diagnosed as lymphocyte depleted and unclassified HD were classified as NHL. As these histologies are dominant in older patients, the incidence of older patients with HD and the total population of HD have decreased since 1980. As a result, the proportion of young adults with a favourable histology has increased. These changes may partly explain the increased patient survival observed both in the national and the hospital population. The hospital population comprised 92% of patients aged 15-39 years, 80% of patients aged 40-59 years and 53% of patients aged > 60 years in the national population. The selection of younger patients in the hospital material may explain a higher survival rate as compared with the national population.

Glucose intolerance after renal transplantation depends upon prednisolone dose and recipient age

BACKGROUND

Retrospective studies on the prevalence of posttransplant diabetes mellitus (PTDM) in patients on triple-drug immunosuppressive therapy have shown great dispersity, while the incidence of posttransplant impaired glucose tolerance (IGT) is unknown. The aim of our study was to prospectively examine the incidence of posttransplant glucose intolerance and to assess potential risk factors.

METHODS

Glucose intolerance was prospectively examined in 173 consecutive kidney transplant recipients by oral glucose tolerance tests (n=167) or the diagnosis of manifest diabetes mellitus (n=6) at 10 weeks after transplant.

RESULTS

We found a high incidence of PTDM (18%) and IGT (31%). Univariate analysis revealed that age, family history of diabetes, HLA-B27 phenotype, DR mismatch, rejection, actual prednisolone dose, total methylprednisolone dose, total steroid dose, cytomegalovirus (CMV) infection, and the use of furosemide were associated with PTDM. Age, prednisolone dose, CMV infection, and the use of beta-blockers were associated with IGT. Gender, body mass index, donor source, and cyclosporine level did not influence glucose tolerance. Prednisolone dose, age, family history of diabetes, CMV infection, and HLA-B27 phenotype were independent predictors of PTDM with the use of multiple stepwise logistic regression analysis. Age, prednisolone dose, and the use of a beta-blocker were associated with IGT in the multivariate model. Both univariate and multivariate linear regression analysis revealed a significant relationship between the 2-hr serum glucose and prednisolone dose. The risk of developing PTDM was 5% per 0.01 mg/kg/day of increase in prednisolone dose.

CONCLUSIONS

Increased prednisolone dose and older age are strongly associated with the development of posttransplant glucose intolerance.

The efficacy of single-dose administration of thrombopoietin with coadministration of either granulocyte/macrophage or granulocyte colony-stimulating factor in myelosuppressed rhesus monkeys

Thrombopoietin (TPO) was evaluated for efficacy in a placebo-controlled study in rhesus monkeys with concurrent administration of either granulocyte/macrophage colony-stimulating factor (GM-CSF) or granulocyte CSF, (G-CSF). Rhesus monkeys were subjected to 5 Gy total-body irradiation (TBI), resulting in 3 weeks of profound pancytopenia, and received either TPO 5 microg/kg intravenously (I.V.) at day 1 (n = 4), GM-CSF 25 microg/kg subcutaneously (S.C.) for 14 days (n = 4), TPO and GM-CSF (n = 4), G-CSF 10 microg/kg/d S.C. for 14 days (n = 3), TPO and G-CSF (n = 4), or placebo (carrier, n = 4; historical controls, n = 8). Single-dose I.V. treatment with TPO 1 day after TBI effectively counteracted the need for thrombocyte transfusions (provided whenever thrombocyte levels were <40 x 10(9)/L) and accelerated platelet reconstitution to normal levels 2 weeks earlier than placebo controls. TPO/GM-CSF was more effective than single-dose TPO alone in stimulating thrombocyte regeneration, with a less profound nadir and a further accelerated recovery to normal thrombocyte counts, as well as a slight overshoot to supranormal levels of thrombocytes. Monkeys treated with TPO/GM-CSF uniformly did not require thrombocyte transfusions, whereas those treated with GM-CSF alone needed two to three transfusions, similar to the placebo-treated monkeys, which required, on average, three transfusions. Also, reticulocyte production was stimulated by TPO and further augmented in monkeys treated with TPO/GM-CSF. TPO alone did not stimulate neutrophil regeneration, whereas GM-CSF shortened the period of neutrophil counts less than 0.5 x 10(9)/L by approximately 1 week; TPO/GM-CSF treatment elevated the neutrophil nadir, but did not further accelerate recovery to normal values. TPO also augemented the neturophil response to G-CSF, resulting in similar patterns of reconstitution following TPO/G-CSF and TPO/GM-CSF treatment. TPO/GM-CSF resulted in significantly increased reconstitution of CD34+ bone marrow cells and progenitor cells such as GM-CFU and BFU-E. Adverse effects of combining TPO with the CSFs were not observed. It is concluded that (1) a single I.V. administration of TPO is sufficient to prevent severe thrombocytopenia following myelosuppression, (2) TPO/G-CSF and TPO/GM-CSF treatment result in distinct response patterns, with TPO/GM-CSF being superior to TPO/G-CSF in stimulating thrombocyte and erythrocyte recovery while being equivalent in stimulating neutrophil recovery; and (3) TPO significantly improves the performance of CSFs in alleviating severe neutropenia.

Lack of efficacy of thrombopoietin and granulocyte colony-stimulating factor after high dose total-body irradiation and autologous stem cell or bone marrow transplantation in rhesus monkeys

The efficacy of recombinant human thrombopoietin (TPO) and recombinant human granulocyte colony stimulating factor (G-CSF) in stimulating platelet and neutrophil recovery was evaluated in a placebo-controlled study involving transplantation of limited numbers (1-3 x 10(4)/kg) of highly purified autologous stem cells (CD34++/RhLA-DR[dull]) into rhesus monkeys after the animals were subjected to 8 Gy of total body irradiation (TBI) (x-rays). The grafts shortened profound TBI-induced pancytopenia from 5 to 6 weeks to 3 weeks. Daily subcutaneous (sc) injection of TPO (10 microg/kg/day, days 1-21 after TBI) did not stimulate platelet regeneration after transplantation either alone or in combination with G-CSF (5 microg/kg/day sc, days 1-21 after TBI). G-CSF treatment failed to prevent neutropenia in the monkeys and did not stimulate recovery to normal neutrophil levels. Simultaneous administration of TPO and G-CSF did not influence the observed recovery patterns. To test the hypothesis that the limited number of cells transplanted or the subset chosen was responsible for the lack of effectiveness of TPO, three additional monkeys were transplanted with 10(7)/kg unfractionated autologous bone marrow cells. Two of these animals received TPO and the other served as a control. In this setting, as well, TPO treatment did not prevent thrombocytopenia. This study demonstrates that treatment with TPO does not accelerate platelet reconstitution from transplanted stem cells after high-dose TBI. These findings contrast with the rapid TPO-stimulated platelet recovery in myelosuppression induced by 5 Gy of TBI in rhesus monkeys; we conclude from this that the clinical effectiveness of the TPO response depends on the availability of TPO target cells in the first week after TBI, that is, before endogenous TPO levels reach the saturation point. In addition, protracted isolated thrombocytopenia was observed in two G-CSF-treated monkeys, one of which also received TPO. Furthermore, TPO treatment for 7 days in the 6th week after TBI during severe thrombocytopenia in one monkey produced prompt clinical improvement and an increase in platelet counts.

Survival, prognostic factors, and therapeutic efficacy in low-grade glioma: a retrospective study in 379 patients

PURPOSE

We report survival, prognostic factors, and treatment efficacy in low-grade glioma.

PATIENTS AND METHODS

A total of 379 patients with histologic intracranial low-grade glioma received post-operative radiotherapy (n = 361) and intraarterial carmustine (BCNU) chemotherapy (n = 153). Overall survival and prognostic factors were evaluated with the SPSS statistical program (SPSS Inc, Chicago, IL).

RESULTS

Median survival (all patients) was 100 months (95% confidence interval [CI], B7 to 113); in age group 0 to 19 years (n = 41), 226 months; in age group 20 to 49 years (n = 263), 106 months; in age group 50 to 59 years (n = 49), 76 months; and for older patients (n = 26), 39 months. Projected survival at 10 and 15 years was 42% and 29%, respectively. Patient age, World Health Organization (WHO) performance status, tumor computed tomography (CT) contrast enhancement, mental changes, or initial corticosteroid dependency were significant independent prognostic factors (p < .05), while histologic subgroup, focal deficits, presence of seizures, prediagnostic symptom duration, tumor category, and tumor stage were not. Patients aged 20 to 49 years with no independent negative prognostic factors (n = 132) had a median survival time of 139 months versus 41 months in patients with two or more factors (n = 33). Patients who presented with symptoms of expansion (n = 97) survived longer when resected (P < .03); otherwise no survival benefit was associated with initial tumor resection compared with biopsy. Intraarterial chemotherapy and radiation doses more than 55 Gy were not associated with prolonged survival. Among 66 reoperated patients, 45% progressed to high-grade histology within 25 months.

CONCLUSION

Prognosis in low-grade glioma following postoperative radiotherapy seems largely determined by the inherent biology of the glioma and patient age at diagnosis.

Spatial training in a complex environment and isolation alter the spine distribution differently in rat CA1 pyramidal cells

The hippocampus is critically involved in spatial learning. Spatial training in adult rats, which improved their spatial learning ability, increased the number of excitatory hippocampal CA1 spine synapses on basal dendrites as compared with either isolated or standardly housed animals (Moser et al. [1994] Proc. Natl. Acad. Sci. USA 91:12673-12675). In this article, we report that spine synapses on oblique apical dendritic branches do not increase in density or number after the same type of training. When examining the variability of the spine density on basal CA1 dendrites by using variance component analysis, the variance associated with the cells was twice as large in all three groups as that coupled to the rats. Analysis of the spine density plots shows that the enhanced spine density after spatial training is found in most cells recorded from the trained group but that a small subset of CA1 neurones are particularly well supplied with spines. The trained group had a significant right-skewed tail of the spine distribution, i.e., training caused high spine density to occur in a small subset of dendritic segments. Conversely, the isolated group had a significant left-skewed spine distribution, indicating that some of the dendritic segments were undersupplied with spines, whereas the paired group displayed no asymmetry.

Differences in the distribution of CD34 epitopes on normal haemopoietic progenitor cells and leukaemic blast cells

The CD34 molecule expressed on haemopoietic progenitor cells contains a large number of epitopes whose expression may be related to the maturation or function of the cells. Monoclonal antibodies specific for different epitopes have been reported to detect different numbers of CD34+ leukaemic blast cells. We wanted to confirm this observation and study whether parallel findings could be observed for normal haemopoietic progenitor cells. The cells were immunophenotyped by flow cytometry with a series of monoclonal antibodies reactive with different CD34 epitopes. Class III epitopes (resistant to enzymatic cleavage with neuraminidase, chymopapain and a glycoprotease from Pasteurella haemolytica) showed a broader distribution on normal haemopoietic progenitor cells and leukaemic blast cells than class I epitopes (sensitive to cleavage with all three enzymes) and class II epitopes (sensitive to degradation with glycoprotease and chymopapain, and resistant to neuraminidase). The subpopulation of normal progenitor cells which exclusively expressed class III epitopes had flow cytometric characteristics compatible with mature myeloid progenitor cells whereas class I, II and III epitopes were equally expressed on cells enriched for immature subsets. No discordant epitope expression could be observed for the more immature leukaemias (AML-M0/1) and a higher percentage of the more mature leukaemic blast cells (AML-M3 and AML-M4/5) expressed class III epitopes compared to the percentage expressing class I and II epitopes. These data indicate that CD34 class III epitopes are more broadly distributed on normal haemopoietic progenitor cells and leukaemic blast cells than class I and II epitopes, and that class I and II epitopes may be down-regulated prior to class III epitopes during normal haemopoietic progenitor cell differentiation. These findings should be considered when selecting CD34 mabs for quantification and positive selection of haemopoietic progenitor cells for research and clinical purposes.

Mutation rate in the hypervariable VNTR g3 (D7S22) is affected by allele length and a flanking DNA sequence polymorphism near the repeat array

The hypervariable human minisatellite locus D7S22 (g3) is highly polymorphic. The allelic distribution in D7S22 features a size clustering of the alleles and a comparably low allelic diversity among small alleles. This reduced diversity could reflect a situation where some alleles are less likely to mutate than others. Several factors could explain such an effect, including allele size, variation in repeat composition, and allelic differences in nearby cis-acting elements affecting the mutation rate. We have characterized 40 de novo mutations found on Southern blots in a large amount of paternity-testing material. There is a significant excess of paternal mutations, and small size changes are most frequent. Mutation rate is affected by allele length, with highest rates in larger alleles. Alleles of the family groups with D7S22 mutations and 50 small alleles were analyzed by nucleotide sequencing. Two hundred thirty-six base pairs of the immediate flanking region upstream of the repeat array were PCR amplified and screened for point mutations by DNA sequencing of the PCR products. Two base substitution polymorphisms were identified: one C/G transversion and one A/G transition, 54 bp and 173 bp upstream of the repeat array, respectively. There is a significant association between mutation and occurrence of 54C, while association is not obvious between mutation rate and the 173A/G variants. There is a marked association between different flanking haplotypes and allele size, and within the smallest allele-size group, all alleles had the 54G/173A haplotype. Both allele size and allelic state at site 54 remain associated with mutation rate when the other factor is controlled. Possible mechanisms behind the variation in mutation rate in D7S22 are discussed.

Lineage commitment of CD34+ human hematopoietic progenitor cells

Hematopoietic cells occur in a continuum of many different stages of functional differentiation, from totipotential stem cells to terminally differentiated lineage-specific cells. At some point during differentiation, progenitor cells become committed to a particular lineage. Little is known about the surface molecules that distinguish lineage-committed progenitor cells from multipotential progenitor cells; this study was undertaken to address this issue. Exploiting a thymic stromal cell co-culture system, we show that CD34+ bone marrow cells expressing the T lymphocyte-associated CD2 and CD7 molecules, the B lymphocyte-associated CD10 and CD19, or the myeloid-associated CD33, contain progenitor cells that can generate T lymphocytes, granulocytes, and monocytes, indicating that the expression of any of these molecules on progenitor cells does not imply lineage commitment. CD34+CD13bright, CD34+CD14+, and CD34+CD15+ cells generated myeloid progeny, and CD34+CD20+ cells failed to differentiate along the T lymphoid and myeloid lineages. Thus expression of CD13, which precedes that of CD14 and CD15 during early hematopoiesis, appears to coincide with commitment to myeloid development. Our findings also indicate that expression of CD20 is restricted to progenitor cells committed to B lymphocyte development.

Haemopoietic progenitor cell differentiation: flow cytometric assessment in bone marrow and thymus

We have recently shown that expression of any of the lineage-associated molecules CD2, CD7, CD10, CD19 or CD33 does not ensure lineage-commitment of CD34+ progenitor cells. Further, normal progenitor cells and leukaemic blast cells have been shown to coexpress molecules associated with more than one haemopoietic lineage. Five-dimensional flow cytometric analysis of normal bone marrow cells was exploited to investigate the hypothesis of a developmental stage in haemopoiesis comprising CD34+ cells coexpressing CD2, CD5, CD7, CD10, CD19 and CD33 or any combination of these molecules. We report on a subpopulation of CD34+ bone marrow cells constituting < 5% of the CD34+ cells and characterized by extensive coexpression of several molecules associated with the B lymphoid, T lymphoid and myeloid lineages. There is every probability that some cells display the CD34+ CD2+ CD5+ CD7+ CD10+ CD19+ CD33+ phenotype. Studies on postnatal thymocytes suggest that this may be the phenotype or one of a few phenotypes of a candidate thymus-seeding progenitor cell population. Finally, our findings that CD34+ as well as CD34+ CD5+ thymocytes can be driven into non-T-lymphoid differentiation by cytokines, support the notion that the thymus is seeded by uncommitted progenitors.